MINNEAPOLIS -- Exploratory surgery performed Tuesday on the right arm and elbow of Detroit Tigers reliever Joel Zumaya by orthopedist James Andrews provided no answers to the pain Zumaya continues experiencing.

Zumaya will be reevaluated in six weeks, and Rand would not rule out his return following the surgery in Pensacola, Fla. Though, he'd earlier said that it's unlikely Zumaya will pitch in 2011.

"He cleaned out the joint," Rand said, "and retracted a screw and put in another in case that was the cause of the pain. This one's a headless screw that buries in (to the bone) deeper."

Zumaya, 26, broke a bone at the tip of his elbow while throwing a pitch on June 29 at Minnesota and had a stabilizing screw inserted July 12 by team orthopedist Stephen Lemos. He did not pitch in a game until Feb. 27, and felt pain after one inning of a Grapefruit Leauge game. Zumaya didn't throw again until April 14, and felt continued pain in the elbow and forearm.

He has not thrown since, and is a free agent after this season.

Rand added that second baseman Carlos Guillen (knee) was to be evaluated Wednesday after resuming "moderate baseball activity" in Lakeland, Fla.

"We'll see how he tolerates that," Rand said.

Guillen has been working with a physical therapist in Tampa and Lakeland.